Chapter 1: The nature of science

1.1 earth science We will learn about Earth and the processes and forces that change it, the materials from which it is made, its long history, and its place in the universe. The Scope of Earth Science Very vast! Dinosaur bones that were once embedded in rocks that make up cliffs and canyons Ocean floor exploration that has led to the discovery of bizarre creatures

Four major areas There are four major areas of specialization in Earth Science: Astronomy Meteorology Geology Oceanography

astronomy Study of objects beyond Earth’s atmosphere Thanks to technology, telescopes are one example, we can study the universe

meteorology Studies the air that surrounds Earth Meteorologist study the forces and processes that cause the atmosphere to change to produce weather They also try to predict the weather and how changes in weather might affect Earth’s climate

geology Study of the materials that make up Earth and the processes that form and change these materials Geologists identify rocks, study glacier movements, interpret clues to Earth’s history, and determine how forces change our planet.

oceanography Study of Earth’s oceans, which cover three-fourths of the planet Oceanographers study the creatures that inhabit salty water, measure different chemical and physical properties of the oceans, and observe various processes in these bodies of water. Some study the effects of human activity on Earth’s saltwater bodies. There are also subspecialties of earth science, listed on page 7

Earth’s systems Scientists have identified 4 main Earth systems: Lithosphere Hydrosphere Atmosphere Biosphere These four systems are interdependent.

Earth’s systems: Lithosphere Rigid outer shell of the planet, includes: the crust and the mantle There are two types of crust: 1. continental crust: made of mostly rock, called granite 2. oceanic crust: mainly basalt, a rock that is denser than granite The mantle is made up of rock called peridotite. Some parts are rigid solid, but some are partially molten and flow like soft plastic (this portion is referred to as the asthenosphere) Under the earth’s mantle is the core Includes 1. outer liquid part and 2. solid inner part

Earth’s systems: Hydrosphere Earth’s water, including oceans, seas, lakes, rivers, glaciers, and the water in the atmosphere all make up Earth’s hydrosphere. Can be either salt water (97%) or fresh water (3%). Fresh water is contained in glaciers, in lakes and rivers, and beneath earth’s surface in groundwater.

Earth’s systems: the atmosphere Blanket of gases that surrounds our planet Necessary for respiration of living things, protects living things against harmful radiation from the sun, and keeps Earth’s temperature suitable for life. Made up of about 78% nitrogen and 21% oxygen and 1% water vapor, argon, carbon dioxide, and trace gases

Earth’s systems: biosphere All organisms on earth as well as the environment that they live in. Includes those that live deep in the oceans and high in the mountains.

Everyday life We live in the biosphere. On the earth’s crust (lithosphere) and breath the gases from the atmosphere. Depend on water (hydrosphere) Technology! Application of scientific discoveries to everyday use.

1.2 methods of scientists

Nature of scientific investigations Scientific method: a planned, organized, approach to solving a problems Steps: Identify the problem, what do you want to know? Suggest a hypothesis, suggested explanation for an observation. Stated in the form of a question that can be answered by the results of a test/experiment Conduct an experiment, an organized procedure that involves making measurements and observations.

In an experiment A good scientific experiment tests only one variable at a time. Independent variable: the factor that is manipulated, or changed, by the experimenter Dependent variable: factor that can change if the independent variable is changed Constants: factors that do not change during an experiment Control: used in an experiment to show that the results of the experiment are actually a result of the condition being tested Mini Lab pg 12

Safety When conducting any scientific investigation, it is important to use all the materials and equipment only as instructed. Look at the safety rules on page 13 Remember in our labs, if you are misbehaving you will be dismissed from the lab and receive a zero.

Analysis and conclusion Carefully record all data, including measurements and observations. When the experiment is concluded, the data is formatted so that it can be studied and analyzed. Graphs, tables, and charts are commonly used to format and display scientific data. This data is then analyzed so that a conclusion can be drawn. Sometimes a hypothesis is not supported by the experiment. In that case, the hypothesis is re-evaluated.

measurement Remember a measurement includes both a number that identifies how many there are and a unit of measure. Most scientific studies use a standard system of units called Le Systeme International d’Unites, or SI for short. This system is based on a decimal system that uses the number 10 as a base unit

Measurement Length Weight and Mass Area and Volume Density Time SI Unit: meter (m) Broken down into 100 cm=1 m, 10mm=1cm So…How many centimeters are in 1 km? Weight and Mass Weight is a measure of the gravitational force on an object, usually measured with a scale. SI Unit: Newton (N) Mass, does not vary with location like weight. It is the amount of matter in an object. SI Unit: kilogram (kg) Area and Volume Area: the amount of surface included in a set of boundaries and is expressed in square units of length (m2). A=L x W Volume: amount of space occupied by an object. SI Unit: Cubic meter (m3), For liquids, volumes are usually in mL Density Measure of the amount of matter that occupies a given space. Calculated by dividing mass by volume. Expressed in g/cm3 Time The interval between two events measured with a clock or watch. SI Unit: second (s) Temperature Measure of the average vibrations of particles that make up material. Measured on Celsius scale or Kelvin Converting from Kelvin to Celsius, Celsius to Fahrenheit

Scientific notation In science, numbers can be very small or very large To conveniently express numbers, scientists use a shorthand call scientific notation to express the number as a multiplier and a power of 10. Let’s practice!

1.3 Communicating in science

Communicating results Important goal in science: make results available to others Lab Reports Used when recording and analyzing information that you collected through your experiment Used to draw conclusions based on your data Can compare to classmates Graphs Visual used to show results of experiments Line graph, bar graph, pie chart Look at figure 1-13 on page 18, line graph comparing 2 variables. Which one is the independent? The dependent? Complete Problem Solving Lab on page 18

Theories and laws Theory: an explanation based on many observations during repeated experiments. Valid only if it is consistent with observations, makes predictions that can be tested, and is the simplest explanation of observations Law: basic principle that describes the behavior of a natural phenomenon “rule of nature” Events observed to be the same every time Example: Sir Isaac Newton’s first law of motion, an object at rest stays at rest, and an object in motion stays in motion, unless it is acted upon by an outside force